The motion of two or more bodies around the Sun on different orbits when it takes them
the same amount of time to complete one revolution. There are three
possible types of co-orbital motions of a small body associated with a planet:
→ tadpole orbits, → horseshoe orbits,
and → quasi-satellite orbits.

Any of satellites which either share the same orbit or which occupy
immediately adjacent orbits that change periodically as the satellites approach one
another (Ellis et al., 2007, Planetary Ring Systems, Springer).